1. Field of the Invention
The present invention relates to a sample introducer, which is suitable for automatically introducing samples into an analyzer such as a total organic carbon (TOC) analyzer.
2. Description of the Background Art
A certain type of a TOC analyzer is applied not only to total carbon (TC) measurement but also to inorganic carbon (IC) measurement, total organic carbon (TOC) measurement, non-purgeable organic carbon (NPOC) measurement, and the like. A sample introducer is provided with a sampling needle for sucking sample solutions as well as a sparging needle for sparging (i.e. blowing a gas into a sample) a gas containing no CO.sub.2 gas into the samples before or during the suction for homogenizing the samples or for sparging the gas into previously acidified sample solutions for removing IC before measuring NPOC. Such needles are individually driven by different driving mechanisms, to be inserted in the sample containers.
In order to perform NPOC measurement, it is necessary to acidify the samples and to remove IC by sparging a pretreatment gas. To this end, the operator manually acidifies all samples and arranges the same on a sample table, so that the ventilation pretreatment needle sparges the pretreatment gas into all samples.
In another type of a TOC analyzer, samples are first introduced into the TOC analyzer, and thereafter subjected to acidification and sparging one by one for NPOC measurement.
When the sampling needle and the ventilation pretreatment needle are individually driven by different mechanisms, the overall structure is complicated.
While the apparatus for entirely sampling previously acidified samples is suitable for NPOC measurement, on the other hand, application of such an apparatus is restricted since this apparatus cannot carry out measurement of other modes such as TC measurement and IC measurement.
In the apparatus for performing acidification and sampling after the samples are introduced into the TOC analyzer, the overall measuring time is increased.